1. Field of the Invention
The present invention relates to a process for preparing hydroxybenzoic esters of oxo alcohols by esterification of hydroxybenzoic acids or transesterification of hydroxybenzoic esters of lower alcohols with reaction mixtures from the oxo process in the presence of a particular acid catalyst.
2. Description of the Background
Esters of hydroxybenzoic acids and in particular 4-hydroxybenzoic acid with higher alcohols, as are obtained from olefins by the oxo process (or hydroformylation), viz. "oxo alcohols", are used to an increasing extent as plasticizers for polymers, in particular for polyamides and polyesters.
Processes for preparing 4-hydroxybenzoic esters by esterification of the free acid with alcohols using solvents such as benzene (V. Varill, J. Chem. Soc. Ind. London 66 (1947) 175, 176), acetone (JP 53112-634) or dioxane (JP 77048-966) are known. These processes employ pure, previously distilled alcohols. In these cases, the solvents are employed as diluents to ensure the stirrability of the reaction mixtures and are sometimes also employed as entrainers for the water of reaction which is formed.